Geology and Ancient Site: China's Huge Plateau's Wind Formation

A new study found that strong winds sculpted the Loess Plateau into the world's largest dust deposit through processes of deposition and erosion. (Photo : Paul Kapp/University of Arizona Department of Geosciences)

New research explains the formation of China's steep-fronted Loess Plateau, an area of consolidated dust and erosion that covers more than 640,000 kilometers in the country's northwest. Geoscientists from the University of Arizona (UA) explained that over the past 2.6 million years, wind has either been depositing dust blown from the Mu Us Desert or sweeping it off to other locations, according to a release.

The researchers compare this method of accumulation to that of a leaf blower pushing a pile of leaves to the edge of one's yard. "If the blower keeps blowing the leaves, they move backward and the pile of leaves gets bigger," Paul Kapp, lead author and UA professor of geosciences, said in the news release. "There's a boundary between the area of leaves and no leaves."

According to the release, the Loess Plateau is the largest accumulation of dust on Earth. The researchers discovered that over time wind forces have carved ridges in the top of the plateau and eroded the face of the plateau, causing it to slowly move downwind.

"You have a dust-fall event and then you have a wind event that blows some of the dust away," Kapp explained in the release. "The plateau is not static. It's moving in a windward direction."

"The significance of wind erosion shaping the landscape is generally unappreciated," Kapp added in the release. "It's more important than previously thought."

The researchers experienced a dust storm first-hand. While atop the plateau during March of 2013, they were able to observe the wind blowing parallel to the ridge's long axis. To better understand the plateau, Kapp compared and mapped ridges captured in Google Earth satellite images.

"I mapped stuff like crazy, for weeks and weeks--I measured the orientation of about three thousand ridges from these images," Kapp said in the release.

His co-author Joellen Russell then mapped modern-day wind patterns over the Mu Us desert and the Loess Plateau. The two compared the orientation of the winds to the orientation of the ridges, and found a perfect match.

"I've never seen anyone look at the wind-related geomorphology and actually relate it to climatology at the large scale of the entire Mu Us Desert and Loess Plateau," Kapp said in the release. "It's a rare approach."

After this, Kapp plans to observe other wind-eroded landscapes. Their research was recently published in the journal Geology.

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